Agree with the others ... pretty much a personal design choice.
That is quite an intricate pattern to work with and you have done a really nice job.
Back tracking is done regularly even in free flowing FMQing.
You just look for the path that can offer the least of that to happen.
.... I usually figure that out, when I am almost done the project!
When I FMQ with stencils or a self-drawn-on design, I use it as a guide, and don't stick it rigidly.
For example, each of my butterflies might be slightly different, just as they would be IRL.
Likewise, each of the feather petals in the centre may look a little different.
For threads ... finer thread (yes you can even go as small as 100 wt) and
thread matched to fabric colour, can both help to camouflage any of your oopsies!
As said already ... personal choices and do it your way!
You have a great sense of design and style in this and your other work, so before long,
you will no doubt feel right at home and your results will certainly show it!